Wednesday, April 13, 2016

LSD and Brain Imaging

We found that under LSD, compared to placebo, disparate regions in the
brain communicate with each other when they don’t normally do so. In
particular, the visual cortex increases its communication with other
areas of the brain, which helps explain the vivid and complex
hallucinations experienced under LSD, and the emotional flavour they can
take.

On the other hand, within some important brain networks, such as the neuronal networks that normally fire together when the brain is at rest,
sometimes called the ‘default mode network’, we saw reduced blood flow —
something we’ve also seen with psilocybin — and that neurons that
normally fire together lost synchronization. That correlated with our
volunteers reporting a disintegration of their sense of self, or ego.
This known effect is called ‘ego dissolution': the sense that you are
less a singular entity, and more melded with people and things around
you. We showed that this could be experienced independently of the
hallucinatory effects — the two don’t necessarily go together...